JPH09144571A - Valve timing control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent worsening of controllability caused by a fluctuation of torque generated in a cam shaft. SOLUTION: An electronic control unit(ECU) 80 stores a correction data determined based on a relation between a cam angle and a torque value generated in a cam shaft 10. The ECU 80 calculates a target displacement angle conforming to an operating condition of an engine 1. The ECU 80 duty controls a linear solenoid valve(LSV) 55 based on prescribed duty ratio. A variable valve timing mechanism 25 is operated by an oil pressure supplied through the LSV 55, and a displacement angle of the cam shaft 10 is changed so as to be the target displacement angle. In the ECU 80, based on the correction data, correction for suppressing worsening of controllability, caused by a torque change of the cam shaft 10, is performed relating to the duty ratio.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve timing control device for controlling the valve timing of at least one of an intake valve and an exhaust valve provided in an internal combustion engine according to the operating state of the internal combustion engine.

[0002]

2. Description of the Related Art In an engine equipped with a valve timing control device, the valve timing can be changed according to its operating condition. That is, the valve timing of at least one of the intake valve and the exhaust valve can be selectively changed from a low speed timing suitable for the low rotation range of the engine to a high speed timing suitable for the high rotation range.

As this type of valve timing control device, the one disclosed in Japanese Patent Laid-Open No. 63-131808 is known. In this valve timing control device, a timing pulley is rotatably provided at one end of a camshaft of an engine, and a cylindrical piston gear is provided between the timing pulley and the camshaft. The piston gear is meshed with the timing pulley and the cam shaft by helical teeth formed on each of them. Therefore, the rotational driving force of the timing pulley is transmitted to the cam shaft via the piston gear. Further, when the piston gear moves in the axial direction of the cam shaft, the displacement angle of the cam shaft changes with the movement.

Further, in the above valve timing control device, the first pressure chamber and the second pressure chamber are provided on the front and rear sides of the piston gear in the axial direction of the camshaft. By adjusting the hydraulic pressures supplied to the first pressure chamber and the second pressure chamber, the piston gear can be moved to a predetermined position in the axial direction of the camshaft. And in this valve timing control device,
By moving the piston gear, the displacement angle of the cam shaft can be changed, and the valve timing of the intake or exhaust valve driven by the cam shaft to open and close can be controlled.

[0005]

However, the valve timing device in the above-mentioned prior art has the following problems.

That is, the intake / exhaust valve is driven to open and close by the camshaft, and at this time, the spring force of the valve spring or the inertial force of the valve itself acts on the camshaft to cause a torque fluctuation at all times. . When torque fluctuation occurs on the camshaft, the position of the piston gear in the axial direction of the camshaft changes, and the displacement angle of the camshaft changes. As a result, there is a possibility that the valve timing cannot be maintained in a stable state with respect to the target value.

When the piston gear is moved to a predetermined position in order to change the valve timing, if the camshaft is fluctuated in torque, the piston gear will not move smoothly and the gear will pulsate. To move. Therefore, it may be difficult to stably move the piston gear to a predetermined position.

As described above, in the conventional valve timing device, the valve timing cannot be stably maintained with respect to the target value due to the torque fluctuation generated in the camshaft, or the piston gear can be stably moved to a predetermined position. As a result of making it difficult to move the device, the controllability of the device deteriorates.

The present invention has been made in view of the above problems, and an object thereof is a valve timing control device for an internal combustion engine capable of preventing deterioration of controllability due to torque fluctuation occurring in a camshaft. To provide.

[0010]

In order to achieve the above object, according to the invention of claim 1, a valve drive cam shaft rotatably supported by an engine body of an internal combustion engine, and the cam shaft are provided. The rotor provided at one end and drivingly connected to the crankshaft of the internal combustion engine, and the teeth provided on the inner circumference interposed between the camshaft and the rotor are external teeth on the camshaft side. And the teeth provided on the outer periphery are meshed with the inner teeth on the rotor side,
In addition, a piston gear in which at least one of the teeth provided on the inner and outer circumferences is a helical tooth, drive means for moving the piston gear in the axial direction of the camshaft to change the displacement angle of the camshaft, and the internal combustion engine Internal combustion engine including a driving state detecting means for detecting the driving state of the vehicle and a control means for controlling the driving means so that the displacement angle becomes a target displacement angle that matches the driving state detected by the driving state detecting means. In the valve timing control device for an engine, the control means, based on a relationship between an operating state of the internal combustion engine and a torque generated in the camshaft in that state, which is obtained in advance, controls the piston gear of the piston gear caused by the variation of the torque. The gist of the invention is to control the drive means while suppressing the position change.

According to a second aspect of the present invention, in the valve timing device for an internal combustion engine according to the first aspect, the operating state detecting means has at least a cam angle detecting means for detecting a rotation angle of the cam shaft, The control means is a command value generating means for generating a control command value for disposing the piston gear at a position where the displacement angle is a target displacement angle adapted to the operating condition of the internal combustion engine, and at least the rotation angle and the torque. From the first storage means, the first storage means in which the correction data determined in advance based on the relationship between the first storage means and the correction data corresponding to the rotation angle detected by the cam angle detection means are stored. Based on the acquired correction data, the position change of the piston gear caused by the torque fluctuation is suppressed with respect to the control command value generated by the command value generation means. And correcting means for performing order of correction is to its gist in that it comprises a first driving control means for driving and controlling the drive means based on the corrected control command value by the correction means.

According to a third aspect of the present invention, in the valve timing control device for an internal combustion engine according to the first aspect, the operating state detecting means has at least a cam angle detecting means for detecting a rotation angle of the camshaft, The control means is
The second storage means stores determination data indicating the rotation angle and the torque state of the camshaft in association with each other, and the torque state of the camshaft causes a torque in a direction opposite to the rotation direction of the camshaft. Positive torque range,
And which region of the negative torque region in which the torque in the same direction as the rotation direction is generated is determined by the rotation angle detected by the cam angle detection means and the discrimination data stored in the second storage means. Based on the determination result by the determining means, when the displacement angle is changed to a target displacement angle that matches the operating state detected by the operating state detecting means, the torque state of the camshaft is determined based on the determination result. The gist of the present invention is to include a second drive control means for driving and controlling the drive means so that the movement operation of the piston gear is performed only when it belongs to either one of the two areas. .

(Operation) According to the first aspect of the invention having the above-mentioned structure, the operating state of the internal combustion engine is detected by the operating state detecting means. Then, the control means controls the drive means so that the displacement angle of the camshaft becomes a target displacement angle adapted to the operating state detected by the operating state detecting means, and controls the piston gear to a predetermined position corresponding to the target displacement angle. To place.

As described above, when the piston gear is arranged at the predetermined position, the control means controls the torque of the internal combustion engine based on the relationship between the operating condition of the internal combustion engine and the torque generated in the camshaft in the operating condition. The drive means is controlled while suppressing the change in the position of the piston gear due to the fluctuation of. Therefore, it is possible to prevent the position of the piston gear in the camshaft axial direction from changing due to the torque fluctuation.

According to the second aspect of the present invention, the command value generating means generates the control command value for disposing the piston gear at the position where the displacement angle of the camshaft becomes the target displacement angle. Further, the first storage means stores correction data which is predetermined based on at least the relationship between the rotation angle of the camshaft and the torque. Then, the correction means acquires the correction data corresponding to the rotation angle detected by the cam angle detection means from the first storage means, and based on the correction data, changes the torque variation with respect to the control command value. Correction is performed to suppress the resulting change in the position of the piston gear. Then, the first drive control means controls the drive means based on the corrected control command value, and arranges the piston gear at a position corresponding to the target displacement angle.

As described above, since the control command value when the first drive control means controls the drive means is corrected to suppress the change in the position of the piston gear due to the torque fluctuation, The piston gear is arranged at a predetermined position corresponding to the target displacement angle in a state where the position change due to the torque fluctuation is suppressed.

As described above, according to the first and second aspects of the present invention, the change in the position of the piston gear due to the torque fluctuation is suppressed. Therefore, for example, when changing the valve timing, the piston gear can be smoothly moved. When the moving operation is executed and the valve timing is held at the target value, the piston gear is held at a predetermined position in a stable state.

According to the third aspect of the invention, in addition to the operation of the first aspect of the invention, the second storage means corresponds to the rotation angle of the camshaft and the state of torque generated in the camshaft. The determination data indicated by the above is stored. Then, the determination means is such that the state of the torque in the camshaft belongs to either of a positive torque region where a torque is generated in a direction opposite to the rotation direction of the camshaft and a negative torque region where a torque is generated in the same direction as the rotation direction. It is determined based on the rotation angle detected by the cam angle detection means and the discrimination data stored in the second storage means. Further, the second drive control means drives and controls the drive means so that the displacement angle becomes a target displacement angle that matches the operating state detected by the operating state detecting means. At this time, the second drive control means performs the movement operation of the piston gear only when the state of the torque in the camshaft belongs to either one of the two regions based on the determination result by the determination device. The driving means is controlled so that

Therefore, the torque generated on the cam shaft when the piston gear moves is only one of the positive torque and the negative torque. Therefore, when the piston gear moves, the urging force acting on the piston gear by the torque of the camshaft is limited to one direction in the axial direction of the camshaft. Therefore, the piston gear is restrained from moving while pulsating in the camshaft axial direction, and the gear smoothly moves to a position where the displacement angle of the camshaft becomes the target displacement angle.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) An embodiment in which the valve timing control device for an internal combustion engine according to the present invention is embodied in a gasoline engine system for an automobile will be described in detail below with reference to FIGS.

FIG. 1 is a schematic configuration diagram showing a gasoline engine system according to a valve timing control device of this embodiment. An engine 1 as an internal combustion engine includes a plurality of cylinders 2. A piston 3 provided in each cylinder 2 can move up and down in each cylinder 2 as the crankshaft 1a rotates.

A combustion chamber 4 is formed above the piston 3 in each cylinder 2. A spark plug 5 is provided corresponding to each combustion chamber 4, and the air-fuel mixture introduced into the combustion chamber 4 is ignited by the spark plug 5. Further, the intake port 6a and the exhaust port 7a provided corresponding to each combustion chamber 4 respectively configure a part of the intake passage 6 and the exhaust passage 7. An intake valve 8 is provided in each combustion chamber 4.
And an exhaust valve 9 are provided corresponding to each valve 8, 9
Thus, the ports 6a and 7a are opened and closed respectively. Each of these valves 8 and 9 operates based on the rotation of different camshafts 10 and 11. The timing pulleys 12 and 13 provided at the tips of the camshafts 10 and 11 are drivingly connected to the crankshaft 1 a via a timing belt 14.

When the engine 1 is in operation, the rotational force of the crankshaft 1a is transmitted through the timing belt 14 and the timing pulleys 12 and 13 to the camshafts 10 and 11, respectively.
And the camshafts 10 and 11 rotate, the valves 8 and 9 are opened and closed. The valves 8 and 9 can be operated at predetermined timings in synchronization with the rotation of the crankshaft 1a, that is, in synchronization with the intake stroke, the compression stroke, the explosion / expansion stroke, and the exhaust stroke according to the vertical movement of each piston 3. Has become.

An air cleaner 15 for cleaning the outside air taken into the intake passage 6 is provided at the inlet of the intake passage 6,
Further, injectors 16 for injecting fuel into the intake ports 6a are provided near the intake ports 6a, respectively. Fuel having a predetermined pressure is supplied to the injector 16 from a fuel tank (not shown) by the operation of a fuel pump. Then, the mixture of the fuel injected from the injector 16 and taken into the intake passage 6 and the outside air is introduced into the combustion chamber 4 through the intake port 6a when the intake valve 8 is opened. In addition, when the air-fuel mixture introduced into the combustion chamber 4 explodes and burns, the piston 3
Also, the driving force of the engine 1 is obtained via the crankshaft and the like. Further, the burnt gas combusted in the combustion chamber 4 is discharged to the outside from the exhaust port 7a through the exhaust passage 7 when the exhaust valve 9 is opened.

A throttle valve 17 that opens and closes in conjunction with the operation of an accelerator pedal (not shown) is provided in the intake passage 6. Then, by opening and closing the throttle valve 17, the amount of intake air into the intake passage 6 is adjusted. A surge tank 18 that smoothes the pulsation of the intake air amount is provided downstream of the throttle valve 17.

An intake air temperature sensor 71 for detecting the intake air temperature is provided near the air cleaner 15 in the intake passage 6. A throttle sensor 7 for detecting the throttle opening is provided near the throttle valve 17.
2 are provided. Further, the surge tank 18 is provided with an intake pressure sensor 73 which communicates with the surge tank 18 and detects the intake pressure.

On the other hand, a catalytic converter 1 having a three-way catalyst for purifying exhaust gas in the middle of the exhaust passage 7
9 are provided. Further, an oxygen sensor 74 for detecting the oxygen concentration in the exhaust gas is provided in the middle of the exhaust passage 7. Further, the engine 1 is provided with a water temperature sensor 75 for detecting the cooling water temperature.

The distributor 21 is the igniter 2
The high voltage output from 2 is distributed to each spark plug 5 as an ignition signal for causing each spark plug 5. Therefore, the ignition timing of each spark plug 5 is determined by the igniter 22.
Is determined by the high voltage output timing from the. The distributor 28 is provided with a rotor (not shown) that rotates in synchronization with the camshaft 11, and a rotation speed sensor 76 that detects the engine rotation speed from the rotation of the rotor. Also, the distributor 21
Is provided with a cylinder discrimination sensor 77 that detects a crank angle reference position of the engine 1 at a predetermined ratio according to the rotation of the rotor and outputs the reference signal.

Further, in the vicinity of the crankshaft 1a,
A crank angle sensor 79 is provided. The crank angle sensor 79 includes a rotor (not shown) connected to the crankshaft 1a and an electromagnetic pickup (not shown).
It is composed of The rotation angle of the crankshaft 1a is detected based on the detection signal of the crank angle sensor 79 and the detection signal of the cylinder discrimination sensor 77. A cam angle sensor 78 for detecting the valve timing of the intake valve 8 is arranged near the intake side camshaft 10, and the cam angle sensor 78 is connected to the rotor to which the camshaft 10 is connected ( (Not shown) and an electromagnetic pickup (not shown). Based on the detection signal of the cam angle sensor 78 and the detection signal of the cylinder discrimination sensor 77, the camshaft 1
A rotation angle of 0 (hereinafter referred to as “cam angle”) θ is detected.

Further, based on the cam angle signal output from the cam angle sensor 78 and the crank angle signal output from the crank angle sensor 79, the crankshaft 1
The actual displacement angle VT of the intake side camshaft 10 with respect to a is calculated. It should be noted that each of the sensors 73, 76 to 79 constitutes an operating state detecting means of the present invention. Further, the cam angle sensor 78 and the cylinder discrimination sensor 77 constitute a cam angle detecting means for detecting the cam angle θ. The detection signals of these sensors 71 to 79 are transmitted to the electronic control unit (hereinafter referred to as “ECU”) of the engine 1 as shown in FIG.
Output) to 80.
The ECU 80 constitutes the control means of the present invention.

A variable valve timing mechanism (hereinafter simply referred to as "VVT") 25, which is driven by hydraulic pressure to make the valve timing of the intake valve 8 variable, is provided on the tip end side of the intake camshaft 10.

The structure of the VVT 25 and the like will be described below. 2 and 3 show a VVT 25 and a linear solenoid valve (hereinafter referred to as “LSV”) 55 attached to the VVT 25.
The structure of is shown. Camshaft 10 is journal 1
At 0a, it is rotatably supported by the cylinder head 26 and the bearing cap 27 of the engine 1. Further, two oil grooves 31 and 32 extending in the circumferential direction are formed in the journal 10a. The bearing cap 27 is formed with oil passages 33 and 34,
The oil passages 33 and 34 allow the journal 10a and the oil grooves 3 to be formed.
Lubricating oil is supplied to 1, 32.

In this embodiment, as shown in FIG.
The oil pan 28, the oil pump 29, the oil filter 30, and the like provided in the engine 1 constitute a lubricating device for lubricating each part of the engine 1. When the oil pump 29 is operated in conjunction with the operation of the engine 1,
The pump 29 sucks and discharges the lubricating oil from the oil pan 28. Then, the discharged lubricating oil is selectively pressure-fed to each of the oil passages 33 and 34 by the LSV 55 through the oil filter 30 and the journal 10a.
And is supplied to the oil grooves 31 and 32.

The housing 36 of the VVT 25 is provided with a substantially disc-shaped timing pulley 12 and a cover 35 attached to the pulley 12. This cover 35
Has a bottomed cylindrical shape and is provided so as to cover one side surface of the pulley 12 and the tip of the camshaft 10. The pulley 12 has a plurality of outer teeth 37 on its outer circumference and a boss 38 at the center thereof. The pulley 12 is rotatably attached to the cam shaft 10 by inserting the cam shaft 10 into the boss 38. The above-mentioned timing belt 14 is hooked around the outer teeth 37 of the pulley 12.

A flange 39 is provided on the outer periphery of the cover 35, and a hole 40 is formed in the center of the bottom. The flange 39 is fixed to one side surface of the pulley 12 by a plurality of bolts 41 and pins 42. A lid 43 is detachably attached to the hole 40. In addition, the cover 35
A plurality of inner teeth 35a, which are helical teeth, are formed on the inner circumference of the.

A cylindrical inner cap 45 and the like are housed in an annular space 44 surrounded by the pulley 12 and the cover 35. The inner cap 45 is fixed to the tip of the camshaft 10 by a hollow bolt 46 and a pin 47. Peripheral wall 45a of the inner cap 45
Is arranged so as to include a part of the boss 38.
5, 38 are relatively rotatable. A plurality of external teeth 45b, which are helical teeth, are formed on the outer circumference of the peripheral wall 45a.
Are formed.

In the annular space 44, a ring gear 48 as a piston gear is interposed between the cover 35 and the inner cap 45, and the gear 48 connects the cover 35 and the camshaft 10. The ring gear 48 has an annular shape and is movable along the axial direction of the camshaft 10. A plurality of teeth 48a and 48b are formed on the inner and outer circumferences of the ring gear 48, and both of them are helical teeth. And ring gear 4
The teeth 48a formed on the inner circumference of the outer ring 8 are the outer teeth 45b of the inner cap 45, and the teeth 48b formed on the outer circumference thereof are the covers 35
Of the internal teeth 35a. By this engagement, when the ring gear 48 moves in the axial direction of the camshaft 10, the shaft 10 rotates relative to the pulley 12. When the pulley 12 is rotated by the rotational driving force transmitted from the timing belt 37, the cover 35 and the cap 45 connected by the ring gear 48 rotate integrally, and the camshaft 10 and the cover 35 rotate integrally. .

As shown in FIGS. 2 and 3, the annular space 44 is formed.
The ring gear 48 causes the first and second hydraulic chambers 49,
It is divided into 50. The first hydraulic chamber 49 is located between the left end of the ring gear 48 and the bottom wall of the cover 37, and the second hydraulic chamber 50 is located between the right end of the ring gear 48 and the pulley 12.

Inside the camshaft 10, there is provided an oil passage 51 for supplying hydraulic pressure to the first hydraulic chamber 49 with lubricating oil.
It is formed along the axial direction of the shaft 10. The tip end side of the oil passage 51 is communicated with the first hydraulic chamber 49 through the hole 46a of the hollow bolt 46, and the base end side is provided with the oil groove 31 through the oil hole 52 extending in the radial direction of the camshaft 10. It leads to.

On the other hand, in order to supply the hydraulic pressure by the lubricating oil to the second hydraulic chamber 50, another oil passage 53 extending parallel to the oil passage 51 is formed inside the camshaft 10. The oil passage 53 and the second hydraulic chamber 50 communicate with each other through an oil hole 54 formed in the boss 38.

In the above structure, the oil passage 33, the oil hole 52,
The oil passage 51, the hole 46a, and the like constitute a first hydraulic pressure supply passage for supplying the hydraulic pressure of the lubricating oil to the first hydraulic chamber 49. Further, the oil passage 34, the oil passage 53, the oil hole 54, and the like constitute a second hydraulic pressure supply passage for supplying the hydraulic pressure of the lubricating oil to the second hydraulic chamber 50. Here, the LSV 55 provided in the middle of both the hydraulic pressure supply passages has its opening degree duty-controlled so that the hydraulic pressure chambers 49, 50 can be controlled.
It controls the hydraulic pressure supplied to. FIG. 1 shows the connection relationship between the LSV 55 and the oil pan 28, the oil pump 29, and the oil filter 30.

The structure of the LSV 55 will be described below. As shown in FIGS. 2 and 3, the casing 56 that constitutes the LSV 55 includes first to fifth ports 57, 58, and 5.
It has 9, 60, 61. The first port 57 communicates with the oil passage 33, and the second port 58 communicates with the oil passage 34. The third and fourth ports 59 and 60 are connected to the oil pan 28, and the fifth port 61 is connected to the discharge side of the oil pump 29 via the oil filter 30. Inside the casing 56 is a skewered spool 6
2 are provided. The spool 62 has four cylindrical valve bodies 62a, and can reciprocate in the axial direction. Further, in the casing 56, an electromagnetic solenoid 63 for moving the spool 62 between the first operating position shown in FIG. 2 and the second operating position shown in FIG.
Is provided. A spring 64 is provided inside the casing 56, and the spring 64 biases the spool 62 toward the first operating position.

As shown in FIG. 3, when the spool 62 is placed in the second operating position against the biasing force of the spring 64, the discharge side of the oil pump 29 and the oil passage 33 are communicated with each other, and the oil passage 34 and the oil pan 28 are communicated with each other. As a result, the lubricating oil is supplied to the first hydraulic chamber 49, and the ring gear 48 rotates while moving in the axial direction against the hydraulic pressure in the second hydraulic chamber 50. Then, the relative displacement angle between the camshaft 10 and the housing 36 changes. Here, as a result of the displacement angle of the camshaft 10 advancing more than that of the pulley 12, the valve timing of the intake valve 8 advances.

On the other hand, as shown in FIG. 2, when the spool 62 is placed in the first operating position, the discharge side of the oil pump 29 and the oil passage 34 are communicated with each other, and the oil passage 33 and the oil pan 2 are connected.
8 is communicated with. As a result, the hydraulic pressure is supplied to the second hydraulic chamber 50, and the ring gear 48 rotates while moving in the axial direction against the hydraulic pressure in the first hydraulic chamber 49. Then, the relative displacement angle between the camshaft 10 and the housing 36 changes in the direction opposite to the above. Here, as a result of the displacement angle of the camshaft 10 being delayed from that of the housing 36, the valve timing of the intake valve 8 is delayed.

In the present embodiment, as described above, VVT2
By controlling 5, the valve timing of the intake valve 8 can be changed continuously (steplessly). Next, the electrical configuration of the ECU 80 will be described with reference to the block diagram shown in FIG.

As shown in FIG. 4, the ECU 80 includes a central processing unit (CPU) 81, a read-only memory (ROM) 82 in which a predetermined control program and the like are stored in advance, and a CPU 8.
A random access memory (RAM) 83 for temporarily storing the calculation result 1 and a backup RAM 84 for storing previously stored data and the like are provided. The ECU 80 is configured as a logical operation circuit in which these units 81 to 84, an external input circuit 85 including an A / D converter, an external output circuit 86 and the like are connected by a bus 87. The sensors 71 to 79 described above are connected to the external input circuit 85. In addition, the injector 1 described above
6, the igniter 22 and the LSV 55 are connected to the external output circuit 86.

The CPU 81 reads the signals of the respective sensors 71 to 79 input via the external input circuit 85 as input values, and executes fuel injection amount control, ignition timing control, valve timing control, etc. based on those input values. In order to do so, the respective members 16, 22, 55, etc. are controlled.

The fuel injection amount control is to control the fuel amount supplied to the combustion chamber 4 by controlling each injector 16 based on the target value calculated according to the operating state of the engine 1. is there. The ignition timing control is to control the ignition timing of each spark plug 5 by controlling the igniter 22 based on the target value calculated according to the operating state of the engine 1. The valve timing control is to control the VTV 25 to control the valve timing of the intake valve 8 by controlling the LSV 55 based on the value of the duty ratio calculated according to the operating state of the engine 1.

In this embodiment, the ROM 82 stores correction data α for correcting the duty ratio during the valve timing control. The correction data α is predetermined based on the relationship between the cam angle θ and the torque generated on the camshaft 10. The correction data α will be described below.

FIG. 5 shows the relationship between the cam angle θ and the torque generated in the camshaft 10. As shown in the figure, it can be seen that the camshaft 10 undergoes torque fluctuations in which the states of "positive torque" and "negative torque" are periodically repeated according to the cam angle. This is because the cam drives the intake valve 8 to open and close as the camshaft 10 rotates.

That is, as shown in FIG. 6A, when the cam 10a of the camshaft 10 pushes down the intake valve 8,
The camshaft 10 has a spring force from a valve spring,
Further, due to the inertial force of the intake valve 8 or the like, a torque (a torque in this direction is defined as “positive torque”) in a direction opposite to the rotation direction of the shaft 10 (indicated by an arrow in the figure) acts.

On the other hand, when the camshaft 10 is in the state shown in FIG. 6B, the torque in the same direction as the rotation direction of the camshaft 10 due to the spring force and the inertial force (the torque in this direction is referred to as "negative torque"). Defined as ") works.

When the camshaft 10 rotates, the "positive torque" and the "negative torque" as described above are alternately applied to the camshaft 10 in accordance with the rotation.
Torque fluctuations as shown in FIG. 5 occur on the shaft 10. Further, the magnitude of this torque fluctuation changes depending on various conditions such as the above-mentioned spring force of the valve spring and inertial force of the intake valve, as well as operating conditions of the engine, that is, intake pressure or engine speed. .

In this embodiment, the correction data α is obtained by the following calculation formula. α = C * SIN {a * (θ−s)} (1) where “C” is a constant determined by the cam lift characteristic, “θ” is the cam angle, and “a” and “a” “S” is a correction value for changing the correction data α in synchronization with the torque fluctuation as shown in FIG. The correction values α and s are set based on the relationship between the cam angle θ and the torque as shown in FIG. FIG. 8 shows the relationship between the cam angle θ and the correction data α obtained by the above calculation formula (1). The relationship between the cam angle θ and the correction data α shown in FIG.
The ROM 82 storing the correction data α constitutes the first storage means of the present invention.

Next, the operation of the valve timing control device constructed as described above will be described. FIG. 7 is a flowchart of a valve timing control routine (hereinafter, referred to as “(VVT control routine)”.
It is executed by the CPU 81 of the CU 80 by a regular interruption every predetermined time.

When the processing shifts to this routine, in step 105, the CPU 81 causes each of the sensors 73, 76 ...
Based on the signal from 79, the intake pressure PM, the engine speed NE, the actual displacement angle VT of the camshaft 10, and the cam angle θ
Read the value of

Subsequently, in step 110, the CPU
81 is the intake pressure PM read in step 105,
A target displacement angle VTT of the camshaft is calculated based on the engine speed NE. The CPU 81 uses this target displacement angle VTT
Is calculated by referring to the function data shown in FIG. In this function data, the target displacement angle VTT is obtained from the relationship between the intake pressure PM and the engine speed NE, and is optimally set in advance by experiments or the like from the relationship between the load LD of the engine 1 and the engine speed NE.

Then, in step 115, the CPU
81 is the target displacement angle VT calculated in step 110
It is determined whether or not the deviation between T and the actual displacement angle VT is less than or equal to a predetermined reference value β (in this embodiment, “3 °”). Then, when the deviation between the actual displacement angle VT and the target displacement angle VTT is larger than the reference value β (when step 115 is “NO”), the CPU 81 proceeds to step 120.

At step 120, the CPU 81
The correction data α corresponding to the cam angle θ read in step 105 is acquired from the ROM 82. And C
In step 125, the PU 81 calculates the correction duty ratio DVTC from the correction data α, the intake pressure PM, and the engine speed NE based on the following calculation formula.

DVTC = F (PM, NE) * α (2) Here, F (PM, NE) represents a function with the intake pressure PM and the engine speed NE as variables, and in the present embodiment, Is defined by the following equation.

F (PM, NE) = K1 * PM * NE (3) K1: Proportional constant Next, the CPU 81 proceeds to step 130 and calculates the set duty ratio DVTS based on the following calculation formula. To do.

DVTS = (VTT-VT) * KP + γ (4) In the above equation, KP is a proportional constant, and γ is a holding duty ratio. When the deviation between the target displacement angle VTT and the actual displacement angle VT is less than or equal to the reference value β in step 115 (step 115 is “YES”), the CPU 81 proceeds from step 115 to step 145. . Then, in step 145, the set duty ratio DVTS is set to the holding duty ratio γ for executing the holding control. Here, the holding control is control for holding the displacement angle of the camshaft 10 at the target displacement angle VTT. In the present embodiment, the CPU 8 that executes the processing of step 130 and step 145.
1 is a target displacement angle VT suitable for the operating state of the engine 1.
It corresponds to command value generating means for generating a control command value for disposing the ring gear 48 at the position T.

Further, the CPU 81 proceeds from step 130 or step 145 to step 135 to perform a correction process on the set duty ratio DVTS. That is,
The CPU 81 sets the set duty ratio DVT as shown in the following equation.
A value obtained by adding the corrected duty ratio DVTC to S is set as a drive duty ratio DVT for duty controlling the LSV 55.

DVT = DVTS + DVTC (5) Then, in step 135, the CPU 81 duty-controls the LSV 55 based on the drive duty ratio DVT. As a result, the displacement angle of the camshaft 10 is retarded or advanced by the VVT 25, and the target displacement angle V
Changed to be TT. In the present embodiment, the CPU 81 that executes the processing of step 135 and step 140 corresponds to the correction means and the first drive control means.

As described above, in the VVT control routine, the actual displacement angle VT of the camshaft 10 is the target displacement angle V
It is controlled to be TT. And step 140
After executing the processing of (1), the CPU 81 waits for a predetermined control cycle and restarts the processing from step 105.

In step 135, the set duty ratio DVTS is corrected, that is, the set duty ratio DVTS is calculated based on the calculation formula (5).
The drive duty ratio DVT is set by adding the corrected duty ratio DVTC to TS. This corrected duty ratio DVTC is calculated by the above-mentioned calculation formulas (1) to (4).
As is clear from the above, the torque changes in synchronization with the torque fluctuation generated in the camshaft 10, and the magnitude thereof changes according to the intake pressure PM and the engine speed NE.

In FIG. 10, the solid line shows the relationship between the drive duty ratio DVT and the cam angle θ when the intake pressure PM and the engine speed NE are constant, and is delayed when the displacement angle of the camshaft 10 is advanced. Each of the case of making the angle and the case of holding the target displacement angle VTT is shown. Further, in the figure, the dotted line shows the relationship between the drive duty ratio and the cam angle θ when the correction process is not performed as a comparative example with respect to the present embodiment.

In the comparative example, the drive duty ratio DVT is constant regardless of whether the displacement angle of the camshaft 10 is advanced, retarded, or maintained.

On the other hand, the drive duty ratio DVT in the present embodiment fluctuates according to the cam angle θ in the same cycle as the torque fluctuation of the camshaft 10 shown in FIG. As described above, the drive duty ratio DVT fluctuates according to the cam angle θ, so that the torque fluctuation of the shaft 10 can be suppressed from affecting the position of the ring gear 48.

A detailed description will be given by taking the case of advancing the displacement angle of the camshaft 10 as an example. Section A in FIGS.
In, when the torque of the camshaft 10 becomes "positive torque", the drive duty ratio DVT temporarily increases. Here, the "positive torque" generated in the camshaft 10
Acts to retard the displacement angle of the shaft 10, in other words, to urge the ring gear 48 toward the tip end side (left side in FIGS. 2 and 3) of the camshaft 10. On the other hand, when the drive duty ratio DVT is temporarily increased, the increased amount is used to advance the displacement angle of the camshaft 10, in other words, the ring gear 48 is moved toward the base end side of the camshaft 10 (right side in FIGS. 2 and 3). ) Acts to bias. Therefore, the "positive torque" causes the ring gear 48
The urging force generated at 1 is canceled by the drive duty ratio DVT temporarily increasing.

In the section B of FIGS. 5 and 10, when the torque of the camshaft 10 becomes "negative torque", the drive duty ratio DVT temporarily decreases. here,
The "negative torque" generated in the camshaft 10 acts to advance the displacement angle of the shaft 10, in other words, to urge the ring gear 48 toward the base end side of the camshaft 10. On the other hand, when the drive duty ratio DVT is temporarily reduced, the amount of the reduction is apparently retarded by the displacement angle of the camshaft 10, in other words, the ring gear 48 is moved toward the tip side of the camshaft 10 (see FIGS. 2 and 3). In the left side). Therefore, the urging force generated in the ring gear 48 by the "negative torque" is canceled by the drive duty ratio DVT being temporarily reduced.

As a result, the ring gear 48 can smoothly move to a position corresponding to the target displacement angle of the camshaft 10 in a state where the position change due to the torque fluctuation generated in the camshaft 10 is suppressed. The case where the displacement angle of the camshaft 10 is advanced has been described above, but in the present embodiment, the same applies to the case where the displacement angle is retarded or the displacement angle is held at the target displacement angle. The position change of the ring gear 48 due to the torque fluctuation is suppressed.

The magnitude of the torque fluctuation generated in the camshaft 10 also changes depending on the operating state of the engine 1 such as the intake pressure PM or the engine speed NE. In the present embodiment, as is clear from the above equations (2) and (3), since the magnitude of the corrected duty ratio DVTC is changed according to the intake pressure PM and the engine speed NE, the torque The position change of the ring gear 48 due to the change can be more reliably suppressed.

FIG. 11 shows the change over time of the displacement angle when the displacement angle of the camshaft 10 is advanced from the actual displacement angle VT ₁ to the target displacement angle VTT ₁ by the VVT control routine described above. . In the figure, the solid line indicates the displacement angle when the correction processing in step 135 described above is performed, and the dotted line indicates the displacement angle when the correction processing is not performed. As shown in the figure, it is understood that when the correction process is not performed, the displacement angle of the camshaft 10 changes to the target displacement angle VT ₁ while fluctuating under the influence of torque fluctuation. Further, it is found that the target displacement angle VT _{1 is} not stable and varies around the same displacement angle VTT ₁ .

When correction processing is performed on this,
Since the influence of the torque fluctuation of the camshaft 10 is suppressed as described above, the displacement angle of the camshaft 10 is smoothly changed and the state where the target displacement angle VTT ₁ is achieved is stably maintained. I understand.

The above-described present embodiment has the following features. (A) According to this embodiment, the position change of the ring gear 48 due to the torque fluctuation of the camshaft 10 can be suppressed. Therefore, when the displacement angle of the camshaft 10 is changed, the ring gear 10 can be smoothly moved, and when the displacement angle is maintained at the target displacement angle, the ring gear 48 corresponds to the target displacement angle. It can be stably held at the position. As a result, in the valve timing control, it is possible to prevent the controllability of the valve timing control from being deteriorated due to the torque fluctuation.

(B) In the present embodiment, the correction data α determined based on the relationship between the cam angle θ and the torque generated in the camshaft 10 is stored in the ROM 82, and based on the correction data α. The drive duty ratio DVT is determined. Therefore, when controlling the valve timing,
It is possible to perform control in anticipation of torque fluctuations occurring in the camshaft 10 in advance, and it is possible to more reliably suppress the position change of the ring gear 48 due to the torque fluctuations.

(C) In the present embodiment, by performing the correction process, the drive duty ratio DVT is changed in synchronization with the torque fluctuation of the camshaft 10, and
The magnitude is changed according to the intake pressure PM or the engine speed NE. Therefore, the position change of the ring gear 48 due to the torque fluctuation can be suppressed more reliably.

(D) When the displacement angle of the camshaft 10 is maintained at the target displacement angle VTT, unnecessary movement of the ring gear 48 due to the torque fluctuation is suppressed. Therefore, it is possible to prevent the inner and outer teeth 48a and 48b of the ring gear 48 from being worn away due to the moving operation.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS. In the present embodiment, VVT25, LCV
The configurations of the 55, the ECU 80, and the like are the same as those of the first embodiment described above, and therefore, the present embodiment will be described below, focusing on the differences from the first embodiment.

In the present embodiment, the ROM 82 serving as the second storage means stores the cam angle θ of the camshaft.
And determination data showing the relationship between the torque fluctuation state generated in the shaft and the torque fluctuation state are stored as a map as shown in FIG. This determination data is determined based on the relationship between the cam angle θ and the torque of the camshaft 10 which is previously obtained by experiments or the like, and the torque acting on the camshaft is the “positive torque” or This is data for determining in which state of "negative torque". Based on this discrimination data, the CPU 81 causes the ring gear 4 caused by the torque fluctuation generated in the camshaft 10.
The valve timing control is performed while suppressing the position change of No. 8. Hereinafter, this control will be described in detail.

FIG. 12 is a flow chart showing the VVT control routine in this embodiment. This VVT control routine is executed by the CPU 81 of the ECU 80 by a regular interruption every predetermined time.

In the present embodiment, the processing from step 205 to step 215 shown in FIG. 12 is the same as the processing from step 105 to step 115 in the VVT control routine in the first embodiment shown in FIG. is there.
When the CPU 81 proceeds from step 210 to step 215, it determines whether the deviation between the actual displacement angle VT and the target displacement angle VTT is less than or equal to the reference value β. And CPU8
If No. 1 determines that the deviation is larger than the reference value β, the process proceeds to step 220.

At step 220, the CPU 81 reads the discrimination data corresponding to the cam angle θ from the ROM 82. Then, the CPU 81 shifts to step 225,
In step 225, the actual displacement angle VT is set to the target phase angle V
In order to match TT, it is determined whether the valve timing should be advanced or retarded. When it is determined that the angle should be advanced (when step 225 is “YES”), the CPU 81 determines in step 2
Move to 30.

At step 230, the CPU 81
Based on the cam angle θ and the determination data read in step 220, it is determined whether or not the torque currently generated in the camshaft 10 is in the “negative torque range”. When it is determined that the torque is not in the "negative torque range", that is, in the "positive torque range"("NO" in step 230), the CPU 81 proceeds to step 260 to set the drive duty ratio DVT. The holding duty ratio γ is set and the process proceeds to step 240. If it is determined that the torque generated in the camshaft 10 is in the “negative torque range” (“YES” in step 230), the CPU 81 proceeds to step 235.

On the other hand, when it is determined in step 225 that the retard should be made (when step 225 is "NO"), the CPU 81 proceeds to step 250. Then, in step 250, the CPU 81
Based on the cam angle θ and the determination data, it is determined whether or not the torque currently generated in the camshaft 10 is in the “positive torque range”. Then, the torque is in the "positive torque range"
If not, that is, if it is in the “negative torque range” (“NO” in step 250), the CPU 8
1 moves to step 255 and the drive duty ratio DVT
Is set to the holding duty ratio γ and the next step 24
Move to 0. Further, when it is determined that the torque generated in the camshaft 10 is in the “positive torque range” (when step 250 is “YES”), the CPU 81 causes the step 2 to proceed.
Move to 35. Note that, in the present embodiment, the CPU 81 that performs the processing of step 230 and step 250 described above.
Corresponds to the determination means.

The above step 230 or step 250
After shifting from step to step 235, the CPU 81 calculates the drive duty ratio DVT based on the following calculation formula. DVT = (VTT-VT) * KP + γ (6) KP: proportional constant corresponding to gain Further, in the step 215, the camshaft 10
Difference between the actual displacement angle VT and the target displacement angle VTT is the reference value β
When it is determined that the following is true (in the case of “YES” in step 215), the CPU 81 proceeds to step 265. Then, in step 265, the CPU 81
Is the drive duty ratio DVT and the holding duty ratio γ
Set to.

Then, each of the steps 235, 260,
When the process proceeds from 255, 265 to step 240, the CP
U81 controls the LSV 55 based on the drive duty ratio DVT, and changes the actual displacement angle VT so that the deviation between the actual displacement angle VT of the camshaft 10 and the target displacement angle VTT decreases. In step 240, the drive duty ratio D
When VT is set to the holding duty ratio γ, CP
U81 determines the displacement angle of the camshaft 10 as the target displacement angle VT.
The actual displacement angle VT as described above
Do not make any changes. The CPU 81 then proceeds to step 24.
After executing the processing at 0, the processing from step 205 is restarted after waiting for a predetermined control cycle. In the present embodiment, the CPU 8 that executes the processing of step 240
1 corresponds to a second drive control means.

As described above, according to the VVT control routine of the present embodiment, when advancing the displacement angle of the camshaft 10, the torque generated on the camshaft 10 is in the "negative torque range". Only at times, LSV55
Is controlled to change the displacement angle. Further, when the displacement angle of the camshaft 10 is retarded, L is set only when the torque generated in the shaft 10 is in the “positive torque range”.
The SV 55 is controlled to change the displacement angle.

As described above, in the present embodiment, the ring gear 48 is provided only when the torque generated in the camshaft 10 is either "positive torque" or "negative torque".
To move the valve timing. Therefore, when moving the ring gear 48 to change the valve timing, the torque of the camshaft 10 limits the urging force acting on the ring gear 48 in one direction in the axial direction of the shaft. Therefore, when the ring gear 48 is moved, the occurrence of pulsation in the moving operation is suppressed, and the ring gear 48 can be smoothly moved to the position where the displacement angle of the camshaft 10 becomes the target displacement angle.

Further, in the present embodiment, for example, when advancing the displacement angle of the cam shaft 10, the cam shaft 10 is rotated clockwise in FIG. 6B due to the movement of the ring gear 48. The direction of this rotation coincides with the direction of “negative torque” generated in the shaft 10. Further, when the displacement angle of the camshaft 10 is retarded, the movement of the ring gear 48 causes rotation in the counterclockwise direction in FIG. 6A, but this rotation direction is the “normal” direction. It matches the direction of "torque".

As described above, in the present embodiment, the direction of rotation of the camshaft 10 accompanying the movement of the ring gear 48,
The valve timing is changed only when the direction of the torque generated in the shaft 10 matches. Therefore, the movement of the ring gear 48 is suppressed from being hindered by the torque, and the driving force during the movement is reduced.

The present embodiment described above has the following features. (A) According to the present embodiment, when the ring gear 48 is moved, it is possible to suppress the occurrence of pulsation due to torque fluctuations. Therefore, the ring gear 10 can be moved smoothly and the displacement angle of the camshaft 10 can be reduced. Can be changed. As a result, it is possible to prevent deterioration of controllability in valve timing control due to the torque fluctuation.

(B) In this embodiment, the ring gear 48
Since the rotation direction of the camshaft 10 accompanying the movement of the shaft 10 and the direction of the torque generated on the shaft 10 are made to coincide with each other, the valve timing is changed.
It is possible to suppress the movement of the vehicle from being hindered by the torque and reduce the driving force during the movement. Therefore, the camshaft 10
The displacement angle changing operation can be facilitated.

The above-described respective embodiments can be implemented by appropriately modifying a part of the configuration as shown below. (1) In the first embodiment, when the displacement angle of the camshaft 10 is changed to the target displacement angle VTT (when step 115 is “NO” in FIG. 7), and the same displacement angle is maintained at the target displacement angle. In any of the cases (YES in step 115), the correction process in step 135 is performed, but the correction process may be performed in either case.

(2) In the first embodiment, the corrected duty ratio DVTC is calculated from the supplementary intake pressure PM, the engine speed NE, and the cam angle θ as shown in the equations (1) to (3). Although it is determined as a parameter, this parameter is not limited to the combination of the intake pressure PM, the engine speed NE, and the cam angle θ. For example, the cam angle θ and the engine speed NE may be used as parameters, or the function F (PM, NE) in the calculation formula (2) may be a constant, and the correction duty ratio DVT may be used.
C may be determined only by the cam angle θ.

(3) In the first embodiment, the corrected duty ratio DVTC is changed linearly with respect to the intake pressure PM and the engine speed NE as shown in the equations (2) and (3). Although set, camshaft 10
The function F (PM, NE) shown in the calculation formula (3) may be changed so that the adaptive control is performed according to the torque fluctuation that actually occurs. Similarly, the calculation formula (1) for obtaining the correction data α may be appropriately changed.

(4) In each of the above-described embodiments, the VVT 25 is provided in which only the valve timing of the intake valve 8 is variable. However, the VVT 25 in which only the valve timing of the exhaust valve 9 is variable, the intake valve 8 and the exhaust valve are provided. VVT25 that makes both valve timings of 9 variable
Can also be provided.

Although the respective embodiments embodying the present invention have been described above, technical ideas that can be understood from the respective embodiments will be described together with their effects. (A) In the valve timing control device for an internal combustion engine according to claim 3, the second drive control means determines the direction of torque in the camshaft and the movement operation of the piston gear based on the determination result by the determination means. The drive means is drive-controlled so that the moving movement of the piston gear is performed in a state where the rotation direction of the camshaft is coincident with the rotation direction of the camshaft.

According to the valve timing control device of the above (a), the second drive control means sets the displacement angle of the camshaft to the target displacement angle which matches the operating condition detected by the operating condition detecting means. The drive means is drive-controlled. At this time, the second drive control means determines the direction of the torque in the camshaft based on the determination result by the determination means,
The drive means is drive-controlled so that the moving operation of the piston gear is performed in a state where the direction of rotation of the cam shaft accompanying the moving operation of the piston gear matches. Since the direction of the torque on the camshaft and the direction of rotation of the camshaft accompanying the movement operation of the piston gear are made to coincide with each other in this way, the driving force for moving the piston gear by the drive means can be reduced. Therefore, the operation of changing the displacement angle of the camshaft can be facilitated.

[0101]

As described in detail above, according to the first or second aspect of the present invention, it is possible to prevent the position of the piston gear in the axial direction of the camshaft from changing due to the torque fluctuation occurring in the camshaft. can do. Therefore, for example, when the valve timing is changed, a smooth piston gear movement operation is executed, and when the valve timing is held at a target value, the piston gear must be held in a stable position at a predetermined position. As a result, it is possible to prevent the controllability of the valve timing control device from being deteriorated due to the torque fluctuation.

In particular, according to the invention of claim 2, the first
Drive control means acquires correction data corresponding to the rotation angle detected by the cam angle detection means from the first storage means, and based on the correction data, the piston gear due to torque fluctuation with respect to the movement control command value. Since the correction for suppressing the position change is performed, the correction for suppressing the influence of the torque fluctuation can be performed on the movement control command value more reliably.

According to the invention described in claim 3, in addition to the effect of the invention described in claim 1, the second drive control means determines that the state of the torque in the camshaft is a positive torque based on the determination result of the determination means. The drive means is controlled so that the movement operation of the piston gear is performed only when it belongs to either one of the region and the negative torque region. That is, when the piston gear moves, the torque generated on the camshaft is either positive torque or negative torque, and the rotational force acting on the piston gear from the camshaft is limited to only one direction. Therefore, it is possible to suppress the occurrence of pulsation in the movement operation of the piston gear, and it is possible to smoothly move the piston gear to a predetermined position corresponding to the target displacement angle.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a gasoline engine system according to a first embodiment.

FIG. 2 is a cross-sectional view showing the structure of VVT and LSV.

FIG. 3 is a cross-sectional view showing the structure of VVT and LSV.

FIG. 4 is a block diagram showing a configuration of an ECU and the like.

FIG. 5 is a diagram showing a relationship between a cam angle and a camshaft torque value.

FIG. 6 is a cross-sectional view for explaining the direction of torque generated in the camshaft.

FIG. 7 is a flowchart showing a “VVT control routine” in the first embodiment.

FIG. 8 is a diagram showing a relationship between a cam angle and correction data.

FIG. 9 is a diagram showing function data relating to a target displacement angle.

FIG. 10 is a diagram showing a relationship between a cam angle and a drive duty ratio.

FIG. 11 is a diagram showing a temporal change in a displacement angle of a camshaft.

FIG. 12 is a flowchart showing a “VVT control routine” according to the second embodiment.

FIG. 13 is a diagram showing a relationship between a cam angle and discrimination data.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine (internal combustion engine), 1a ... Crank shaft (output shaft), 8 ... Intake valve (valve), 10 ... Cam shaft, 12 ... Timing pulley (rotating body), 35a ...
Internal teeth (rotor side internal teeth), 45b ... External teeth (camshaft side external teeth), 48 ... Ring gear (piston gear), 48
a ... Inner teeth (inner teeth of piston gear), 48b ... Outer teeth (outer teeth of piston gear), 49 ... First hydraulic chamber, 50 ... Second hydraulic chamber (49, 50, etc.) constitute drive means. ) 73 ... Intake pressure sensor, 76 ... Revolution sensor, 77 ... Cylinder discrimination sensor, 78 ... Cam angle sensor, 79 ... Crank angle sensor (7
Reference numerals 3, 76 to 79 constitute an operation state detecting means, and 78, 7
Reference numeral 9 constitutes cam angle detection means), 81 ... CPU (control means, command value generation means, correction means, first and second drive control means, judgment means), 82 ... ROM (first)
And second storage means).

Claims (3)

[Claims] 1. A valve driving cam shaft rotatably supported by an engine body of an internal combustion engine, and a rotating body provided at one end of the cam shaft and drivingly connected to a crank shaft of the internal combustion engine, The teeth provided on the inner circumference of the cam shaft and the rotating body are meshed with the outer teeth of the cam shaft side, and the teeth of the outer circumference are meshed with the inner teeth of the rotating body. And a piston gear in which at least one of the teeth provided on the inner and outer circumferences is a helical tooth, drive means for moving the piston gear in the axial direction of the camshaft to change the displacement angle of the camshaft, and the internal combustion engine An operating state detecting means for detecting an operating state of the engine; and a control means for controlling the driving means so that the displacement angle becomes a target displacement angle that matches the operating state detected by the operating state detecting means. A valve timing control device for an internal combustion engine, comprising: a control means for controlling the internal combustion engine operating condition of the internal combustion engine, and the torque generated in the camshaft in that state. A valve timing control device for an internal combustion engine, wherein the drive means is controlled while suppressing a change in the position of the piston gear due to a change in torque. 2. The operating state detecting means includes at least a cam angle detecting means for detecting a rotation angle of a cam shaft, and the control means sets a target displacement angle at which the displacement angle matches an operating state of an internal combustion engine. Command value generating means for generating a control command value for arranging the piston gear at a position, and correction data that is predetermined based on at least the relationship between the rotation angle and the torque is stored. And the correction data corresponding to the rotation angle detected by the cam angle detection means from the first storage means, and generated by the command value generation means based on the correction data. Based on the control command value corrected by the correction unit, a correction unit that corrects the control command value for suppressing the position change of the piston gear due to the torque fluctuation, A valve timing control device for an internal combustion engine according to claim 1, further comprising: first drive control means for driving and controlling the drive means. 3. The operating state detecting means includes at least a cam angle detecting means for detecting a rotation angle of a cam shaft, and the control means associates the rotation angle with a torque state of the cam shaft. The second storage means that stores the determination data shown, the torque state in the camshaft, a positive torque region in which torque is generated in the direction opposite to the rotational direction of the camshaft, and a negative torque in the same direction as the rotational direction A determination unit that determines which region of the torque region it belongs to based on the rotation angle detected by the cam angle detection unit and the determination data stored in the second storage unit; and the displacement angle. When changing to a target displacement angle suitable for the operating condition detected by the operating condition detecting means, the torque condition of the camshaft is determined based on the judgment result by the judging means. A second drive control means for controlling the drive of the drive means so that the moving operation of the piston gear is performed only when the control means belongs to either one of the two areas. A valve timing control device for an internal combustion engine as described above.